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More power captain! Or when sprinkler valves fail…


For the Minnesota Roller Girls roller derby game in February they played in the Xcel Energy Center, which was awesome!  The place holds a ton of people, which is great for MNRG, but presents a challenge for the T-Shirt cannon, as the calculations were set for the Roy Wilkins Auditorium.  So, I went about changing the dimensions of the cannon to shoot T-Shirts twice as far!  Bassicly, I cut the accumulation chamber in half, added a 3″ PVC T, and 13″ more of 3″ PVC pipe.  This allowed us to get the force to shoot further, but also meant that we would only get two shots out of it. Continue reading

MNRG Raspberry Pi powered T-Shirt Cannon

Photo of MNRG T-Shirt Launcher

Wet Spot 2.0 Holding the Minnesota RollerGrils T-Shirt Cannon 2.0

Last year I was asked to repair the Minnesota RollerGirls T-Shirt Cannon that failed mid-season.  I created a temporary fix, just in time before the game. The repair got us talking about the future of T-Shirt launching technology. What would make this cooler? How can we improve this technology to make Launcher 2.0?

Minnesota RollerGirls’ Wet Spot (Lucas Saugen) and I started brain storming.  We met for lunch and started throwing around ideas.

What could we do better? In five years, where will the technology of T-Shirt launching be?  How can we make sure that there wouldn’t be a T-Shirt Cannon technology gap at the Minnesota RollerGirls?

Also, how can we make it so that the darn thing doesn’t break every season.

T-Shirt Cannon of past.

Former Cannon, mid fix on the operating table

This blog post details some of the build, process, and technology that went into making the new Raspberry Pi powered T-Shirt Cannon for the awesome Minnesota RollerGirls team!

First we came up with a list of things that we wanted for the new T-Shirt Cannon. This would ensure it would be a viable technology for future games and entertainment.

Our Ideas:

  • Tweet – (Yes, Tweet when it has launched a T-Shirt)
  • Camera – To capture that special moment of hitting someone in the face.
  • “Capture all the stats!” Tweet the stats about the launch
  • Launch more than one shirt in a time-out period, which is ~60-90 seconds.

We also got ideas from the teams:

Raspberry Pi Power Cat Feeder – Updates

Back in February 2013 I started teaching my Raspberry Pi 101 class. After the first class I think I had Pi on the brain, I was scheduled for a quick weekend trip out of town with my girlfriend, and she was due to leave her two cats behind. She said that she was going to leave a large bowl of cat food out, and with that I suggested that I build an automated cat feeder for them.

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Ya know, so the cats don’t over eat, and maybe have a mixture of food, and it’s super cool! (Did I mention that it’s cool!?) So… five days before leaving town, I purchased the food hopper, and very quickly ran out of time to complete the project before leaving on vacation. So plan B it was, a large bowl of cat food, and water.

However, I did stick with my original plan, and saw the build to completion well before my next trip out of town. In this blog post, I’ll list out the step-by-step (for the most part) process to building your very own Wifi Enabled Raspberry Pi Powered Cat/Human Feeder.

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